I have Windows Vista Home Premium and I downloaded VirtualDub 1.7.8 because I have a project that I want to start working on. I'm using a tutorial for practice before I start my project, so I'm using the files that the tutorial provided. When I tried opening the video file on VirtualDub it said:

Couldn't locate decompressor for format 'WMV3' (unknown)

VirtualDub requires a Video for Windows (VFW) compatible codec to decompress video. DirectShow codecs, such as those used by Windows Media Player, are not suitable.

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I searched for a VFW compatible codec that could be used with VirtualDub but it didn't work. Is this just my computer being stupid or did something completely fly over my head? Thank you for helping me out, my mind is completely fried right now.

Yes, sorry, I should have made this clear. But the OP has already gotten past the point of opening the source file. VirtualDub is now complaining about not finding a WMV3 decoder. So either he has the WMV source plugin already, or his WMV3 video is in another (AVI?) container.

Originally Posted by DarrellS

WMV9VCM is an encoder (Video Compression Manager).

I thought it included a VFW decoder too, but I just checked and found it only includes the VFW encoder.

sorry for the question but I have problems w/ this program, too.. I've installed all things required, done the things you've recommended here, and it's still not working, cannot find the vfw codec... but I'm sure I have one. I've already had K-Lite codec before, installed DivX codecs... what's the problem?

You'll probably need to find ffdshow's folder in your Start menu, click on 'VFW configuration.' In the window that pops up, make sure you're on the Decoder tab, and that Codecs is highlighted in the left side of the window. Scroll down on the right until you find the codec that VirtualDub can't 'find.' In the Decoder column for that codec, click on the dropdown and set it to libavcodec.

Thanks for your help!
I've tried what you said, but sadly it doesn't work. Btw I've installed the K-Lite pack, DivX, DivX Pro VFW, Xvid.. that's all I guess. They all worked pretty good with the other editing programs.
And I think it matters that it's VirtualDubMod, not 'only' VirtualDub.
It's an MKV file I want to open, and there are two error messages (if there are, because sometimes it simply froze..):
1. MKV: Subtitle stream (2) contains overlapping subtitles. Some of the may not be kept when editing. ---> I think it's not a big deal since I want to remove the subtitles from this file anyways...
2. Couldn't locate decompressor for format ???? (unknown). VirtualDub requires a Video for Windows (VFW) compatible codec to decompress video. DirectShow codecs, such as those used by Windows Media Payer, are not suitable. Only 'Direct Stream Copy' is available for this video.

VirtualDubMod's support for MKV is rather outdated, and can't handle h.264/AVC video through the VfW interface at all (that's why you get the "Cannot locate decompressor for format ˙˙˙˙" message).

Since all you want to do is remove the subtitle stream, install mkvtoolnix instead, and use MKVMergeGUI (mmg.exe) from the package to delete the subtitle stream. (Uncheck the box next to the subtitle stream, after you've loaded the video, and remux to a new MKV.)

You might also want to install MKVExtractGUI while you're at it, to the same directory as mkvtoolnix, just to have it handy. (You won't need it for the above, but it's useful to have around if you're going to do a lot of work with MKVs.)

2. Couldn't locate decompressor for format ???? (unknown). VirtualDub requires a Video for Windows (VFW) compatible codec to decompress video. DirectShow codecs, such as those used by Windows Media Payer, are not suitable. Only 'Direct Stream Copy' is available for this video.

Given that you have an MKV file, my guess is you need an h.264 decoder. ffdshow has a VFW h.264 that VirtualDubMod can use.

Use MediaInfo to get information about your files. It will tell you what audio and video codecs are used.

VirtualDubMod's support for MKV is rather outdated, and can't handle h.264/AVC video through the VfW interface at all (that's why you get the "Cannot locate decompressor for format ˙˙˙˙" message).

Since all you want to do is remove the subtitle stream, install mkvtoolnix instead, and use MKVMergeGUI (mmg.exe) from the package to delete the subtitle stream. (Uncheck the box next to the subtitle stream, after you've loaded the video, and remux to a new MKV.)

You might also want to install MKVExtractGUI while you're at it, to the same directory as mkvtoolnix, just to have it handy. (You won't need it for the above, but it's useful to have around if you're going to do a lot of work with MKVs.)

Thanks so much - one more question, then I'll try handle this on my own
Can I convert the MKV files to AVI with this program?

//okay, I'm silly, I figured out that I cannot... of VirtualDubMod's acting like that and I need to convert it fast, what can I do?

Right now, I'm using AVIDemux to convert MKVs to AVI. It takes a bit of getting used to, though, and may not run as well depending on your hardware (at least it did in my experience - it runs great on the system listed in my profile, but on the Vista32 system I was using before that (dual-core with 1GB RAM), it ran a lot slower, even with the process priority increased.

You might try some of the ffmpeg/mencoder GUI converters like Avanti and WinFF. It's also possible to frameserve an MKV into VirtualDub/Mod using AVISynth scripts, but that's not for beginners and may require a little experimentation to make sure the video and audio remains in sync.

XviD codec installed, but anyway I can not figure out its settings, I mean where to specify the frame size, frame per sec, average bitrate and others, those utilities in XviD codec directory for me are useless